Solution mining or the in-situ leaching of uranium is a relatively recent development which allows economical uranium recovery from lower grade ores which are otherwise (by traditional mining, crushing, beneficiation, etc.) too expensive to process. A solution containing (NH.sub.4).sub.2 CO.sub.3 and an oxidant (H.sub.2 O.sub.2 or dissolved O.sub.2) is pumped into an ore body where the uranium is oxidized to the soluble +6 oxidation state, causing it to enter the leaching solution. The solution is then pumped out of the ore body and is processed to recover the uranium contained in it. The uranium is usually recovered by passing the solution over an ion-exchange resin to which the uranyl carbonate complex attaches. It can then be eluted off the column and precipitated as ammonium diuranate.